1. Field of the Invention
The present invention relates to an apparatus for feeding a plastics molding machine with labels to be attached to the surface of a molding within the molding machine, and also to a method of producing plastics moldings.
2. Description of the Prior Art
An U.S. patent application Ser. No. 85/722,317 filed Apr. 11, 1985 and, entitled "Intra-mold Label Dispenser", discloses an invention which relates to a label feeding apparatus for feeding labels to walls of a mold cavity for forming plastics. This application issued as U.S. Pat. No. 4,585,408 on Apr. 29, 1986. A corresponding Japanese application Sho. No. 61-83198 was filed Apr. 10, 1986 with a declaration of priority at the Japanese Patent Office, and was laid open to public inspection on Oct. 22, 1986 under the number 61-237,620.
The "intra-mold label dispenser" comprises:
a base located near a mold and provided with label magazines for storing labels therein;
a sub-base movably mounted on the base so as to be reciprocatable between opened mold parts;
a first actuator provided on said base for reciprocating the sub-base;
a shuttle movably provided on said sub-base so as to be movable toward and away from said mold;
a second actuator provided on said sub-base for actuating the shuttle;
a label carrier fixed to said shuttle such that it can take labels out of said magazines; and
a controller for operating said first and second actuators, said controller having: a label conveying step in which said shuttle is moved toward said label magazine, labels are taken out of said label magazines by said label carrier, and said second actuator is driven to move said shuttle to a position in which the labels can be inserted into the mold in the opened state; a label setting step in which said sub-base is moved by said first actuator to transfer the labels from said label carrier to one of the mold; and a return step in which said sub-base is returned to its original position for the next cycle.
In the "intra-mold label dispenser", labels are positioned at label-attachment portions of the mold by causing the second actuator to move the label carrier to the proximity of the label attachment portions when the sub-base is positioned in the gap between the opened mold parts.
When the prior art intra-mold label dispenser is used to feed labels to a mold which is opened and closed along at least one pair of tie bars, the label carrier with labels thereon must be passed between the tie bars of the pair so as to place the labels in proper positions relative to the mold cavity walls after the mold has been opened.
In this prior art label dispenser, however, the sub-base or the shuttle cannot be adjusted with respect to their height or angular position relative to a horizontal plane, and the presence of the tie bars hinders the advance of the label carrier to the cavity walls. Therefore, there is a problem in that the label carrier and the labels must be made smaller when the label dispenser should be used with a mold associated with a pair of tie bars. The prior art label dispenser has another problem in that, when the label dispenser is used for various types of molds having different heights, the locations where the labels are to be attached, or the position of the labels placed in such locations relative to the molds, cannot be changed.